Is the refrigerator killing my yeast?

[Fionnbharr]

I've been unable to brew for a couple of weeks because I've had three yeast starters in a row fail to ... well, fail to 'start'.

I've been storing the WL vials on the top shelf in the kitchen refrigerator, out of the way, in the back. I'm bringing them up to room temperature before pitching in cooled (74-78 F) starter wort.

This is the first time I've had yeast just putz out like this. And to have it three times in a row? Makes me think I'm doing something wrong. Could it be too cold in the refrigerator?

 

[BigFloyd]

Could it be too cold in the refrigerator?

Not unless it's cold enough to hard freeze your yeast.

How do you know if your starters are failing or not? If you happen to be using a stir plate, very often you won't get much (if any) krausen even though the yeast are multiplying like bunny rabbits.

 

[jtratcliff]

Your fridge IS killing your yeast... It now has the taste for blood.... Protect your family man! GET OUT NOW!!!!!


Actually, what BigFloyd said...

I've pitched many questionable starters made from 6+ month old washed yeast thinking "Man, nothing is going on in there"... only to have fermentation to kick off gang busters in primary.

 

[insanim8er]

It would take ice to puncture the cell walls and kill the yeast. Agree you taking gravity readings?

 

[Fionnbharr]

The yeast isn't freezing, so I don't think the cell walls are getting damaged that way.

I'm just getting Nothing. I usually end up with quite a bit of yeast at the bottom of the container -- multiple volumes of the original yeast I put in. Now, I'm not getting much at all; not much more than the original yeast volume plus a little bit I'm sure I can attribute to break material from the wort itself.

 

[BrewerinBR]

Step them up, pour out the old wort and add new wort.

 

[BigFloyd]

The yeast isn't freezing, so I don't think the cell walls are getting damaged that way.

I'm just getting Nothing. I usually end up with quite a bit of yeast at the bottom of the container -- multiple volumes of the original yeast I put in. Now, I'm not getting much at all; not much more than the original yeast volume plus a little bit I'm sure I can attribute to break material from the wort itself.

Stop rinsing.

It could very well be that you're dumping out a good portion of your viable cells via that process. I used to rinse and have slowly become convinced to cease the practice. Just harvest and store in the refrigerator (under a layer of the beer it came from).

 

[pdxal]

What does it look like when you cold crash the starter? I agree, you probably have plenty of yeast cells present, but don't realize it. Why not check the gravity of the starter wort before pitching and then after a couple of days to see if there has been activity you didn't notice?

 

[Fionnbharr]

I pitched what I had, yesterday. There'sactivity in the fermenter, so something worked.

I'm just going to collect whats at the bottom of the fermenter, put it in a 2-cup canning jar (instead of the 1/4-cup ones I've been using), and go from there.

Thanks, everyone!

 

[HB_brewer]

Are you using new WL vials of yeast for your starters? did you check the date on them? What yeast are you using?

Your starting temp is a little higher than I normally do for my starters, but you should be fine.

You really need to take OG and FG readings on your starter if you want to be absolutely sure fermentation/yeast growth is happening.

What sugar are you using in your starter?

I usually see a lot of activity with my WLP004 yeast in my starters using light DME. I get it to about 1.030-1.040 and it goes like gang busters and I get a bunch of good yeast after a day or two, then I put it in the fridge to make most of the yeast fall out and pour out the top to save the good yeast for my next batch of beer

 

[Fionnbharr]

Are you using new WL vials of yeast for your starters? did you check the date on them? What yeast are you using?

Depends. Occasionally I'll use new yeast if it's been a while since I've used the strain. Otherwise, I'll pitch harvested yeast.

Your starting temp is a little higher than I normally do for my starters, but you should be fine.

The temperature is ambient room temperature in the garage. You probably live somewhere cold.

You really need to take OG and FG readings on your starter if you want to be absolutely sure fermentation/yeast growth is happening.

Well, that's an indirect inference, so I wouldn't go so far as to say 'absolutely sure'. A better measurement would be direct cell counts under the microscope.

What sugar are you using in your starter?

I use a standard 10:1 water-to-Extract ratio by weight using DME.

I usually see a lot of activity with my WLP004 yeast in my starters using light DME. I get it to about 1.030-1.040 and it goes like gang busters and I get a bunch of good yeast after a day or two,

So you say you're top-cropping. Good on ya.

then I put it in the fridge to make most of the yeast fall out and pour out the top to save the good yeast for my next batch of beer

Yep, that's the way it's done.